Thomas Ewing III (21 May 1862, Leavenworth, Kansas, USA – 7 December 1942, Yonkers, New York) was the 33rd Commissioner of the U.S. Patent Office, serving between 1913 and 1917.

[1] At that time, his father, Thomas Ewing, Jr., was the Chief Justice of the Supreme Court of Kansas but he resigned his position to recruit an Army infantry regiment and to fight for the Union.

[3] Ewing grew up in Washington, D.C. (1865–1870), and Lancaster, Ohio (1870–1879), while his father worked as a lawyer and a U.S.

[6][7] By then, he had gained memberships in the Sigma Chi fraternity and, in 1885, Phi Beta Kappa society.

[16] Thomas made his name as the counsel for Frank J. Sprague on the multiple-unit control of electric train operations and for Professor Michael I. Pupin on long-distance telephony.

[19] The other was the National Research Council (NRC), organized in 1916 to oversee the scientific and technical services for the war effort.

The NRC was asked by Ewing to assemble a committee specifically to prepare the legislation to reform the patent laws.

It eventually succeeded in having the Lampert Patent Office Bill passed by the Congress – in 1922,[19] five years after the end of Ewing's term.

[29][30] This board encouraged the munitions and aircraft industries to pool their patents to help the technological development for the war effort.

[5][17] He was also active in the operations of three local hospitals, the Hollywood Inn (a workingman's club built in Yonkers by his father-in-law[34][35]), and the New York Juvenile Asylum (now Children's Village).

[3][5][17] His metrical translations of Horace, from the Latin, also appeared in the American magazine, Poet Lore.

[44][45][46][47][49] When Thomas was the Commissioner, the Ewings lived across Lafayette Square from the White House at 1607 H Street, N.W., in Washington, D.C.[51] Their home was named the Slidell House after its previous resident, Senator John Slidell of Louisiana.